Everything You Need to Know About Boost Converter

Boost converter image source Wiki

We have two keywords to think of: ‘Boost’ and ‘Converter’. A boost converter, also known as a step-up converter, is an electric device or circuit that converts DC-DC while simultaneously increasing the circuit’s voltage output.

So, this is not an AC-DC converter as most electric converters do.

Boost converters are also known as switch mode DC-DC converters because their operation mechanisms make them turn on and off quickly.

The circuit receives the input energy and stores it in the inductor. It then releases it at a higher voltage.

A boost converter is commonly used to convert low voltage that is coming from a DC source such as a battery to a higher voltage such as the one on a wall adapter. This is why we are referring to it as DC-DC converter. The overall result of this conversion is a high output energy and at the same time better energy efficiency in linear power supplies.

Components of a boost converter

We have to recognize the fact that a boost converter is the simplest type of switch mode converter. This is derived from the fact that it has very few electronic components combined to form a functional circuit.

The key components of a boost converter include:

• Inductor: The main function of an inductor in a circuit is to store energy which will, later on, be released at a higher voltage. A typical inductor comprises of a wire wrapped around a magnetic material. When the boost converter is turned on, electric current will flow through the inductor where it will be stored. When you turn the converter off, the stored voltage will be released.
• Input voltage source: This is the low-voltage current that is coming from a DC source. It is the voltage that needs to be boosted to a higher voltage. The voltage source can be a battery or any other DC source.
• Switch: Like any other switch, it controls the flow of current to the boost converter. A switch on this device comes in two main options, it can be a BJT or MOSFET. When turned on, it will allow current to flow to the inductor and load. When off, it releases the voltage from the inductor.
• Diode: A diode of a boost converter blocks the current from flowing back through the switch without causing any damage. Keep in mind that the new voltage will be higher than the input voltage, so it will be a major risk if it flows back to the source. The diode is connected in parallel with the load and hence will allow the current to be unidirectional.
• Capacitor: This is also connected parallel to the load and it smoothens the sine wave of the output voltage. It accumulates and stores electric charge when the boost converter is on.  Later on, it will release the stored charge when the converter is off so that the output voltage remains constant.
• Control circuit: A boost converter also has a control circuit whose main function is to regulate the output voltage. The circuit adjusts the duty cycle of the switch so that the output voltage remains at a constant level.

Working principle of a boost converter: How it works

The working mechanism of a boost converter is based on the principle of an inductor to store and release energy when needed. The voltage drop across the inductor is directly proportional to the electric current that flows through the boost converter. The arrangement ensures that the DC output to the load is always regulated.

The operation of a boost converter is divided into two main phases

1. When the switch is On and the Diode is Off
2. When the switch is off and the Diode is On

Let’s discuss these two phases and what happens at each phase.

When the switch is On and Diode is Off

In this phase, you have turned on the main switch that controls the operation of a boost converter. The diode is open or in an off-state. Turning on the switch will allow an electric current to flow through.

Current gets to the MOSFET through the inductor and the capacitor stays charged. There is a gradual accumulation of current in the inductor.

This current will flow through a closed circuit: from switch-inductor-back to the DC source. In an OFF state, the diode is reverse-biased hence no current flows through it.

The switch is Off and the diode is On

In this phase, the switch or MOSFET is turned off hence stopping the flow of current to the inductor. Remember that the main function of an inductor is to maintain a smooth flow of current. Cutting of the supply suddenly will force the inductor to generate a higher voltage whose polarity is opposite to that of the initial supply voltage.

The new voltage is derived from the magnetic field created in the inductor. Since the polarity of the inductor is reversed, the diode will be forward-biased allowing current to flow through.  The new voltage will be higher than the initial one but sufficient enough to run the target load.

Applications of boost converters

Boost converters are used in applications that require the conversion of DC power from a lower voltage to a higher DC voltage. Here are some common applications of these converters:

• Battery charging systems: The converters increase the voltage for an efficient charging system. Devices such as mobile phones take advantage of this technology.
• LED lighting: Some LED lighting systems require more power than what the DC source can supply.
• High voltage power supplies: Most industrial applications require high voltage supplies and this may require boost converters to be used.
• Electric vehicles: There are many situations when EVs need more power than what the battery pack is supplying. For example, when executing overtakes. Boost converters come in handy.
• Audio amplifiers: The converters ensure that more power is delivered to the amplifiers.
• Renewable energy power sources such as solar and wind power.

What do you intend to use a boost converter for? Share your idea and we will help you achieve it. Would you like to import boost converters in China wholesale? We will still help you.

I hope that you have learned some valuable insights about boost converters and you can comfortably include one in your application.

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